Improvement in locks for doors



T. KRO M EB. Locks, for Doors, &c.

Patented July 1, 1873.

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UNITED STATES A LPrrrrnv'r OFFICE.

THEODORE KROMER, OF FREIBURG, GRAND DUCHY OF BADEN IMPROVEMENT IN LOCKSFOR DOORS, &c.

Specification forming part of Letters Patent N 0. 140,377, dated July 1,1873; application led April 17, 1873.

To all whom it may concern:

Be it known that 1,'1HE0D0RE KROMER, of Freiburg, in the Grand Duchy ofBaden, have invented an Improvement in Locks; and do hereby declare thatthe following description, taken in connection with the accompanyingsheet ot' drawings hereinafterreferred to, forms a full and exactspecification of the same, wherein I have set forth the nature andprinciples of my said improvement, by which my invention may bedistinguished from others of a similar class, together with such partsas I claim and desire to secure by Letters Patent,

that is to say- My invention has reference to the construction of locksfor which Letters Patent of the United States of America were granted tome' on the 19th of September 1871, No. 119,036.

My present improvement on such locks is represented on the accompanyingdrawings, in which Figure 1 shows a front view of the lock with thecover-plates removed, showing the sliding bolt in the unlocked position.Fig. 2 shows the sliding bolt and latch in the locked position. Fig. 3shows a section on line X X, Fig. 1. Fig. 4 shows a section on line Y Y,Fig. 1. Figs. 5 and 6 show respectively a plan and a section of the key;and Fig. 7 is a similar section to Fig. 4, showing a modifiedconstruction of the notched or grooved sliding pins to adapt the lockfor use as a combination lock without a key.

One part of my invention has reference to the construction of thenotched sliding pins and key. The sliding pins a (Figs. 3 and 4) areformed with a tapering or conical projection, a, on their front ends,which, when the pins are in the forward or locked position vare situatedin holes b1 ot' small diameter formed in the projection b2 of the casingb, as shown at Fig. 3. The pins c of the key c (Figs. 5 and 6) areformed with tapering or conical recesses at their front ends, as shown,which, when the key is inserted into the lock for pushing back thesliding pins t onto the tapering ends a of the latter. The recess ofeach key-pin is made of a different depth and taper, so that the ends ofthe sliding pins (which are all made of the same length and taper forone lock) enter the recesses of their respective key-pins to varyingdepths. By this arrangement it is rendered very difficult to ascertainthe distance to which the sliding pins have to be pushed in, in order tobrin gall the deep or real grooves or notches thereof into position forunlocking, and it is also rendered very difficult to take a properimpression of the key for the purpose of making a false key, andgthusthe probability of the lock being pickedis rendered very remote. Anotherpart of my invention consists in providing in the casing of the lock,below each sliding pin, a pin, d, (Fig. 4,) fitting into a recess in thecasin g and pressed upward by a spring, d', so as to catch with Aitsupper end into the false or real grooves or notches of the sliding pina. By the action of these spring-pins in catching into and pressingagainst each groove of the sliding pin as this is slid back for thepurpose of bringing the real groove into the position for unlocking, itis rendered very difficult, if not impossible, to feel when the hingedlatch e falls with itsvknifeedgesc1 into the real groove of the slidingpin in attempting to pick the lock. Another part of my invention hasreference to the sliding 'boltf (Figs. 1 and 2) ot' the lock and itsmode of operating in combination with the hinged latch e. The latch,instead ot' having the projections upon its outer end, described in mybeforementioned patent, is simply provided with an inclined face, e2.The sliding bolt f has on its lower face a spring-stud, j", which whenthe latch e is in the raised or locked position and the bolt f is alsoin the locked position, as atFig. 2, projects in front of the inclinedface of the latch, and thus prevents the bolt f from being slid backfrom its locked position.

Ou the latch c falling into the unlocked position (shown in dotted linesat Fig. 2) by the introduction of the key, its upper face is just belowthe spring-stud f1, and the sliding boltf can consequently be slid backinto the unlocked position by means ot' the lever and handle at g. Thesliding bolt j' is furthermore provided with a stud or projection, f2,which, on the backward motion of the bolt, presses against the inclinedend face c2 ot' the latch, and thus raises the same up so as to allowthe sliding pins a to spring forward into the locked position. As thelatch is thus raised up the spring-stud f of the bolt f is pressedupward thereby, as shown in Fig. 1,

and on the boltfbeing again slid forward into the locking position thespring stud, after passing the end of the latch e, again springs down infront of the same, thus locking the bolt, as before described.

In order to keep the knife-edge el of the latch c raised out of thefalse notches of the sliding pins, when in the locked position, so as tofacilitate the pushing back of the sliding pins by means of the key forunlocking, the springstud f1 is, by preference, formed with an inclinedface, as shown, which is made to press against the inclined face e2 ofthe latch e, so as to raise it, by means of a spring, h, fixed to thecasing of the lock, which tends to press the bolt f backward, when inthe locked position, as shown in Fig. 2. In this case, after theintroduction of the key for unlocking, the bolt f must first be pressedslightly forward against the action of the spring h by means of thehandle at g, in order to free the latch e from the pressure of the studf1, whereupon the latch will fall into the unlocked position, and thebolt f can then be slid back.

The above-described lock may be adapted to act as a combination lock,and opened Without the use of a key. For this purpose the springs to thegrooved sliding pins a are dispensed with, and the front ends of thesliding pins are extended so as to project through the `holes b1 of thecasing, as shown at c2, Fig. 7, and the projecting ends are providedwith knobs whereby the pins a can be slid back-- ward and forward byhand. As the springpins d, by springing into the grooves or notches ofthe sliding pins c, will act as ratchets in retaining them in anyposition into which they are moved by hand, it will be seen that theoperator, knowing the position of the real groove or notch relative tothe false grooves in each of the pins a, can readily bring each of thelatter successively with their real grooves in correct position for theknife-edge of thel latch e to enter thein for unlocking, by counting thcnumber of times that the spring-pin catches into the grooves while he ismoving the sliding pins. The relative positions of the sliding pins a,(the real grooves or notches of which have a dii'erent position in eachpin, as described in my before-mentioned patent,) may be changed at willby removing the back plate z' of the casing, so that a number ofdifferent combinations, depending on the number of sliding pins in thelock, may be obtained, whereby the picking of the lock will be renderedas difcult as in any other known construction of combination locks.

Having thus described the nature of my invention, and in what manner thesame is to be performed, I claiml. The notched or grooved sliding pinsa, with tapering or conical ends al, operating in combination with thekey c, with pins cl having conical or tapering recesses, substantiallyas and for the purposes hereinbefore described.

2. The spring-pins d operating in combination with the sliding pins a,substantially as and for the purposes hereinbefore described.

3. The sliding boltf with spring-stud f1, and stud or projection f2,operating in combination with the hinged latch e with inclined face e2,substantially as and for the purposes hereinbefore described.

4. The spring l1., operating in combination with the sliding bolt f,spring-stud f1, and hinged latch e, substantially as and for thepurposes hereinbefore described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses this 29th day of January, 1873.

'IHEODORE KROMER.

Witnesses HEINRICH SPITZ, ERNST SCHMITT.

